Aluminum bronze alloy containing vanadium and manganese and having improved wear resistance



United States Patent ALUMINUM BRONZE ALLOY CONTAINING VA- NADIUM ANDMANGANESE AND HAVING IM- PROVED WEAR RESESTANCE John F. Klement,Milwaukee, Wis., assignor to Ampco Metal, Inc., Milwaukee, Wis., acorporation of Wisconsin No Drawing. Filed Oct. 27, 1961, Ser. No.148,038

6 Claims. (Cl. 75-462) This invention relates to an aluminum bronzealloy and more particularly to an aluminum bronze alloy containing asmall addition of vanadium and manganese and having improved wearresistance.

In drawing operations for sheet and plate alloys such as stainlesssteel, aluminum, nickel, titanium, mild steel and some copper basealloys, the dies are often fabricated from aluminum-bronze alloys. Thealuminum bronze alloys used in die applications have good corrosionresistance, Wear resistance and are non-galling against many wroughtmaterials.

The aluminum bronze alloys which in the past have shown the optimumproperties for deep drawing dies are those which contain approximately14% aluminum, a small amount of iron and the balance copper. Alloys ofthis type have good corrosion resistance and nongalling properties.However, under heavy use in die applications, an alloy of this typewears undesirably fast so that close dimensional tolerances cannot bemaintained because of the wear that occurs in the die surface.

The present invention is directed to an aluminum bronze alloy which hasthe corrosion resistance and the non-galling properties characteristicof aluminum bronze alloys, but has improved wear resistance, toughnessand hardness. These increased physical properties are brought about bythe addition of a small amount of vanadium and manganese. Thecombination of vanadium and manganese tends to make the alloy morehomogeneous in the distribution of the metallurgical phases andcompounds during solidification and heat treatment and also promotesuniform, controlled grain size. The alloy has improved machinability andis less susceptible to eutectoid transformation and its embrittlingstructure.

The alloy of the invention has the following general composition byWeight:

Percent Aluminum 13.0-18.0 Iron 2.06.0 Vanadium 0.012.5 Manganese 0.506.0 Copper Balance The alloy falling within the above range ofcomposition has a tensile strength in the range of 70,000 to 100,- 000p.s.i., a yield strength of 50,000 to 80,000 p.s.i., an elongation intwo inches up to 3% and a Rockwell C hardness in the range of 25 to 55.

A specific illustration of the composition of the alloy falling withinthe above range is as follows in weight percent:

Percent Aluminum 14.50 Iron 4.25 Vanadium 1.00 Manganese 3.00 Copper77.25

In addition to the above elements, small amounts of impurities can bepresent in the alloy up to an amount of about 0.50% without alfectingthe basic properties of the alloy.

This alloy can be cast either statically or centrifugaL ly and in thecentrifugally cast state the alloy has a tensile strength of 90,000p.s.i., a yield strength of 72,000 p.s.i., an elongaton in two inches of0.5% and a Rockwell C hardness of 40.

The alloy of the invention has greatly improved wear resistance over theconventional aluminum-ironcopper alloy due to the addition of vanadiumand manganese. The wear resistance of the alloy is determined on arolling-slip friction device such as an Amsler wear test machine. In thetest procedure, a cylindrical aluminum bronze alloy test specimen issubjected to rolling and sliding motions against an 18-8 stainless steelcylinder of identical dimensions with a 15 kilogram load applied on thespecimens. The wear rate is determined copper had a wear rate of 0.00200gram per 1000 revolulutions in the testing procedure.

With a wear test procedure such as this, a standard aluminum bronze diealloy containing 14.5% aluminum, 4.5% iron and 81.0% copper had a wearrate or weight loss of 0.00256 gram per 1000 revolutions and a RockwellC hardness of 39. In comparison with this, the alloy of the inventioncontaining 14.70% aluminum, 4.60% iron, 0.75% vanadium, 1.0% manganeseand 78.95% copper had a Wear rate of 0.00200 gram per 1000 revolutionsand a Rockwell C hardness of 40. From these test results it can be seenthat the wear resistance of the alloy was increased about 22% by theaddition of vanadium and manganese, while the hardness of the alloy wasnot increased to any appreciable extent.

Generally, the wear rate of the alloy of the invention containing thevanadium and manganese additions is in the range of 0.00160 to 0.00210gram per 1000 revolutions per 15 kilogram load, as measured by an Amslerwear testing machine against 18-8 stainless steel. In addition, thealloy has a hardness in the range of 25 Rockwell C to 55 Rockwell C,depending on the specific aluminum, iron, vanadium and manganesecontents in the alloy.

The alloy of the invention has greatly improved wear resistance overthat of an ordinary aluminum bronze alloy and this increase in wearresistance is most significant since the hardness of the alloy is notappreciably changed over the aluminum bronze alloy having similarproportions of aluminum and iron, but not containing the vanadium andmanganese. This unexpected increase in wear resistance without anincrease in hardness is believed to be due to the formation of anintermetallic compound formed predominately of iron, vanadium andmanganese and containing aluminum and copper. This intermetalliccompound in the form of small particles is extremely hard and resistantto wear.

The metallographic structure of the alloy consists essentially of agamma two phase which is uniformly distributed in a matrix of beta. Theintermetallic compound composed of iron, vanadium, manganese, aluminumand copper exists in small particles of uniform size and shape which aredistributed throughout the phases.

If the vanadium content of the alloy is increased over 2.5%, additionalquantities of vanadium will come out of solution as intermetallicparticles, which will make the particles extremely rich in vanadium andcause pickup or galling of the workpiece. If the vanadium content isreduced below the lower limit of the aforementioned range, there is noappreciable efiect shown in the increase in wear resistance.

The manganese serves to retard eutectoid development and its embrittlingstructure. If the manganese content is increased over 6.0%, themanganese tends to take up excessive quantities of the aluminum andother additives and makes the melt diificult to control. Moreover, ifthe manganese is increased beyond 6%, the

thermal conductivity of the alloy will be decreased to a value makingthe alloy unsuitable for die applications where rapid heat transfer fromthe die surface is important.

In order to obtain optimum properties, the metal used for the alloyshould be of high quality. Electrolytic or wrought fire-refined copper,high purity aluminum, low carbon iron, and high purity vanadium andmanganese are preferred to be used. It has been found that the bestmethod of obtaining the desired uniformity in the alloy is by using adouble melting procedure whereby a pre-alloy is made. The pre-alloy isone that has approximately 60% aluminum, 20% iron, vanadium and copper.In the melting procedure this prealloy is melted in the crucible with anadditional quantity of a copper-manganese alloy. Alternately, thevanadium and manganese can be employed in the pre-alloy which, ifcontaining vanadium and manganese, will generally consist of 50%aluminum, 16% iron, 22% copper, 4% vanadium and 8% manganese.

It is not necessary to heat treat the alloy of the invention. However,in some applications, a conventional stress relieving treatment can beemployed and, because of the manganese, the alloy can be stress relievedwithout embrittlement due to excessive eutectoid formation.

The alloy of this invention can be used to produce articles for wearresistant application in drawing and forming operations. The articlesmay take the form of deep drawing dies, hold down dies, wear guides,forming rolls, skids, slides and the like.

The alloy can also be extruded into Weld rods and weld wire. The alloyin the form of coated or uncoated weld rod can be overlaid on a metalbase by metal spraying or other welding methods such as heliarc, carbonare, metal are and the like to obtain a corrosion resistant wearsurface.

It has been found that the addition of vanadium and manganese to thecopper-aluminum-iron alloys to be used as die materials greatly improvesthe toughness and wear resistance of the alloy and makes it lesssusceptible to eutectoid embrittlement.

In addition, the alloy of the invention has not only increasedtoughness, strength, and wear resistance but also has improvedmachinability by controlling the distribution of the various componentphases. The improved machinability permits die sinking of more intricatedesigns on die surfaces than was previously possible on ordinaryaluminum bronze die alloys.

Various modes of carrying out the invention are contemplated as beingwithin the scope of the following claims particularly pointing out anddistinctly claiming the subject matter regarded as the invention.

I claim:

1. An aluminum bronze alloy, consisting essentially by weight of 13.0 to18.0% aluminum, 2.0 to 6.0% iron, 0.01 to 2.5% vanadium, 0.50 to 6.0%manganese and the balance being substantially copper, said alloy beingcharacterized by having excellent corrosion resistance and improvedtoughness and wear resistance.

2. An aluminum bronze alloy, consisting essentially by weight of 13.0 to18.0% aluminum, 2.0 to 6.0% iron, 0.01 to 2.5% vanadium, 0.50 to 6.0%manganese and the balance being substantially copper, said alloy beingcharacterized by a tensile strength in the range of 70,000 to 100,000p.s.i., a yield strength in the range of 50,000 to 80,000 p.s.i., anelongation in two inches of up to 3%, and hardness in the range of 25 toRockwell C.

3. An aluminum bronze alloy, consisting essentially by weight of 13.0 to18.0% aluminum, 2.0 to 6.0% iron, 0.01 to 2.5% vanadium, 0.50 to 6.0%manganese and the balance being substantially copper, said alloy havinga wear rate in the range of 0.00160 to 0.00210 gram per 1000 revolutionsper 15 kilogram load of frictional work as measured on a rolling-slipwear testing machine against 18-8 stainless steel.

4. A deep drawing die characterized by having excellent corrosionresistance, a hardness in the range of 25 to 55 Rockwell C and improvedwear resistance, said die being fabricated from an aluminum bronze alloyconsisting essentially by weight of 13.0 to 18.0% aluminum, 2.0 to 6.0%iron, 0.01 to 2.5% vanadium, 0.50 to 6.0% manganese and the balancebeing substantially copper.

5. An aluminum bronze alloy, consisting essentially of 14.5% aluminum,4.25% iron, 0.75% vanadium, 3.0% manganese and 77.25% copper, said alloybeing characterized by having excellent corrosion resistance andimproved toughness and wear resistance.

6. An aluminum bronze welding electrode, consisting essentially byweight of 13.0 to 18.0% aluminum, 2.0 to 6.0% iron, 0.01 to 2.5%vanadium, 0.50 to 6.0% manganese and the balance being substantiallycopper.

References Cited in the file of this patent UNITED STATES PATENTS1,074,285 Nolan Sept. 30, 1913 1,811,682 Binney June 23, 1931 2,778,733Frejacques Jan. 22, 1957 2,874,042 Klement Feb. 17, 1959 2,937,941Klement May 24, 1960 3,025,158 Klement Mar. 13, 1962 FOREIGN PATENTS703,304 Germany Mar. 6, 1941 UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION Patent No. 3,147,113 I September 1, 1964 John F, Klement Itis hereby certified that error appears inthe above numbered patentreqliri ng correction and that the said Letters Patent should read as'corrected below.

Column 2, line 15, for "copper had a wear rate of 0.00200 gram per" readby the weight loss of the test speoi-men in Signed and sealed this 29thday of December 1964.

(SEAL) Attest:

ERNEST w; SWIDER EDWARD J. BRENNER Attesting Officer Commissioner ofPatents

1. AN ALUMINUM BRONZE ALLOY, CONSISTING ESSENTIALLY BY WEIGHT OF 13.0 TO18.0% ALUMINUM, 2.0 TO 6.0% IRON, 0.01 TO 2.5% VANADIUM, 0.50 TO 6.0%MANGANESE AND THE BALANCE BEING SUBSTANTIALLY COPPER, SAID ALLOY BEINGCHARACTERIZED BY HAVING EXCELLENT CORROSION RESISTANCE AND IMPROVEDTOUGHNESS AND WEAR RESISTANCE.